Thiophen Analogues of Quinoline

Thiophen Analogues of Quinoline. - Pyrolysis of 3-(2-thienyl)propenal O-methyloxime at 650°C in a silica tube gave a 33% yield of thieno[3,2-h]-pyridine.New methods for the synthesis of 3-cyanopyridine-2-thiones 

Thiophen Analogues of Quinoline.— Interest in the chemistry of thieno-pyridines is continuing. Thieno[3,2-b]pyridine has been prepared in 80% yield through the zinc-chloride-catalysed condensation of 3-aminothiophen hydrochloride with malonic aldehyde acetal. Reaction of the 2-amino-3-benzylthiophen (425) with l-nitro-2,2-bis(methylmercapto)ethylene (426) gave the thieno[2,3-b]pyndine derivative (427) in 29% yield. 5-Ethylthieno- 

Thiophen Analt es of Isoquinoline.— The methyl derivatives (448) and (449) were prepared by principally new routes. Starting from the lithium 

46ta Shvedov, I. A. Kharitzomenova, and A. N. Grinev, Khim. geterotsikl. Soedinenii, 1974, 58. 

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Thiophen Analogues of Quinoline.—Cyclization of (96) by treatment with AICI3 gave 4-amino-5-cyanothieno[2,3-/)]pyridines. 4-(Acylamino)thieno[2,3-f7]-pyridines were obtained from (186). 4-Amino-5-cyanothieno[2,3-Z>]pyridones were synthesized from 2-amino-3-cyanothiophens and ethyl cyanoacetate in the presence of sodium ethoxide. These compounds showed antibacterial activity. Through the reaction of 2-chloro-3-cyano-pyridines with ethyl thioglycollate followed by base-catalysed ring-closure, 3-aminothieno[2,3-6]pyridines were prepared, and these were transformed into various derivatives, including tricyclic systems. ... 

Thiophen Analogues of Quinoline and Related Compounds.—Convenient methods for the synthesis of the thiophen analogues of quinoline have been worked out. By the condensation of 2- and 3-thienylanunonium hexachlorostannates with malonic aldehyde tetraethyl acetal, thieno-[2,3-6]pyridine (538) and thieno[3,2-6]pyridine (539) were obtained in 44% and 77% yields. With other /5-dicarbonyl compotmds, substituted derivatives were obtained. Thus, acetoacetaldehyde dimethyl acetal gave... 

Thiophen Analogues of Indole, Quinoline, Isoquinoline, and Similar Systems... 

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